[FASTFAT]
After renaming a directory, rename any children FCB that would still exist in the FSD. This will allow next directory opening to properly work and open correct data.
This defeats corruption on directory renaming.
Unfortunately, this solution is not ideal and our driver should be reworked so that it quits using a hash table and it quits storing the whole path in the FCBs.

Deep thanks to Wim Hueskes and Thomas Faber for their help debugging the issue!